That is really interesting to hear! I am quite cautious about what I do in any environment, of course. How would you say WSL without windows defender compares (security-wise) with say, running equivalent operations with homebrew or macports in OS X? Or just in vanilla bare-metal linux?
Windows Defender protects from Windows malware entering via WSL and Linux malware as well.
For example Windows Defender has caught comprimised npm modules inside WSL.